Two basic approaches, not mutually exclusive: 1) make advertising expenditure non-deductible or weaker version treat as investment, make deduction multi-year reducing NPV 2) directly tax ad revenue, strength depends on rate.

My motivation is treating ads as mental pollution and force for centralization and monopoly, not preventing election manipulation. Complaints abut the latter are nothing but extreme hypocrisy coming from the US.

I like the idea. Ads could be treated as pollution.

> How would taxing ads be different than just taxing corporations?

Without commenting on the wisdom or relevance of the proposal, this seems really simple. Taxing activities disincentivizes them, so you could expect a tax on a specific activity to have the first order effect of reducing that activity.

Tldr: lower advertising budgets

The corporations in question pay very little taxes in the first place, getting them to pay their fair share would be nice.

But I don't think that would change their negative influence on the society.